Automatic tank gauge systems

ABSTRACT

A level sensor mechanism for detecting liquid levels in storage tanks. A conduit is provided having an upper portion and a lower portion. The conduit may be adapted to receive a cable therein, may be substantially rigid and adapted to resist deflection. A sensor assembly body is provided and adapted to locate a level sensor therein. The sensor assembly body may be located in fixed relation to said conduit, and may be rigidly composed and adapted to resist deflection. A coupling member may be secured to said lower portion of said conduit, said coupling member fixedly securing said conduit to said sensor assembly body, said sensor assembly body being secured on said offset portion of said coupling member. The level sensor mechanism may thereby resist or eliminate deflection through the construction of the conduit, coupling member and sensor assembly body.

TECHNICAL FIELD

The present invention relates generally to level sensors for use inunderground tanks, and in particular but not by way of limitation, to alevel sensor mechanism that provides for simple insertion of the sensorinto the tank, and allows the level sensor mechanism to fixedly place alevel sensor therein for accurate level sensing.

BACKGROUND OF THE INVENTION

In typical underground tank storage systems, such as those used atfuel-filling stations, a tank fill pipe extends from ground level to atop portion of the tank. Within the tank fill pipe, a drop tube extendsfrom ground level to a position near the bottom of the tank. There is arelatively small, set clearance between the tank fill pipe and the droptube.

In the tank storage systems in which fuel is stored, the tanks maycontain both fuel and water. These tanks are typically made of metal orceramic materials, such as fiberglass. Level sensor mechanisms have beenprovided to detect both the fuel and water for many different reasons,such as ensuring an adequate fuel supply, tracking the amount of fuel inthe tank, determining leakage in the tank, determining the amount ofwater in the tank, etc. Such level sensor mechanisms have included theuse of floats and the like to either provide feedback based on theposition of the floats, or to assist in maintaining a level sensormechanism in proper position.

Other level sensor mechanisms have provided therewith shafts that extendto the bottom of the tank for stability, but are allowed to at leastpartially swing. These level sensor mechanisms at least partially swingthrough either the choice of materials provided on these level sensormechanisms, which are typically metallic, through the use of buoyancydevices, such as floats and the like, or combinations thereof. Thesehave proven problematic for several reasons.

First, these level sensor mechanisms may frictionally contact a surfaceof the tank. Over time, given that the liquid stored in the tank willrepeatedly be drained and filled, the frictional contact will force agradual wearing down of the tank, thereby exposing the environment todamage due to leakage of hazardous materials and the like storedtherein. This problem is especially apparent when the level sensormechanism has a metallic portion.

Second, the sensor inside of these level sensor mechanisms may provideaberrant feedback, given the movement of the level sensor mechanism overtime. Re-calibration of theses sensors would therefore be required on amore frequent basis.

Third, the number of parts for these level sensor mechanisms may beexcessive, especially when buoyancy devices are provided with the levelsensor mechanisms. Because of the large number of tank storage systems,it is prohibitive to have intricate level sensor mechanisms that arecostly.

Fourth, a majority of these level sensor mechanisms may have theadditional problem of being difficult to install within a tank. Becausethese level sensor mechanisms typically have electrical wiringassociated therewith, the level sensor mechanism is installed in anunused bung, which requires a disinterring of the tank and subsequentrepair of the surface. This is both costly and disruptive.

SUMMARY OF THE INVENTION

To overcome these and other problems, the principles of the presentinvention provide for a level sensor mechanism for a storage tank. Aconduit is provided having an upper portion and a lower portion. Theconduit may be adapted to receive a cable therein, may be substantiallyrigid and adapted to resist deflection. A sensor assembly body isprovided and adapted to locate a level sensor therein. The sensorassembly body may be located in fixed relation to said conduit, and maybe rigidly composed and adapted to resist deflection.

A coupling member may be secured to said lower portion of said conduit,said coupling member fixedly securing said conduit to said sensorassembly body, said sensor assembly body being secured on said offsetportion of said coupling member. The level sensor mechanism may therebyresist or eliminate deflection through the construction of the conduit,coupling member and sensor assembly body.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood with regard to the followingdescription, appended claims, and accompanying drawings, with likereference numerals denoting like elements where:

FIG. 1 is a side plan view of the level sensor mechanism in accordancewith the principles of the present invention;

FIG. 2 is a top plan view of an exemplary coupling member for the levelsensor mechanism of FIG. 1;

FIG. 3 is an exemplary side plan view of the coupling member of FIG. 2connected to a sensor assembly body;

FIG. 4 is an exemplary schematic of the installation in a storage tankof the level sensor mechanism of FIG. 1;

FIG. 5 is a partial isometric view of the level sensor assembly of FIG.1 in a storage tank;

FIG. 6 is an exemplary partial isometric view of coupling means for thelevel sensor mechanism;

FIG. 7 is a cross-sectional view of the exemplary connector means takenalong lines 7—7 of FIG. 6.

DETAILED DESCRIPTION

A level sensor mechanism for a tank storage system is provided which,after installation, fixedly depends into a tank. The level sensormechanism provides feedback through a level sensor secured in the levelsensor mechanism to an instrumentation system, which may be coupled to adisplay device. When the tanks are filled with the desired liquids, thelevel sensor mechanism remains in one position, which may therebyeliminate aberrant feedback from the sensor and may also reduce contactbetween the sensor level mechanism and the tank.

Referring first to FIG. 1, there is shown a side view of the levelsensor mechanism 10 formed in accordance with the principles of thepresent invention. Level sensor mechanism 10 is designed for placementinto a tank 500. Level sensor mechanism 10 includes a substantiallyrigid conduit 20 having an upper portion 30 and a lower portion 40, andis adapted to receive a cable 50 therein. The conduit 20 may bespecifically adapted to resist or avoid deflection. A coupling means 60is provided for coupling the conduit 20 to a tank fill pipe 510 (FIG.5), and may abut a drop tube 520. The coupling means 60 facilitatesconnection of the level sensor mechanism 10 to the tank fill pipe 510(FIG. 5), and may be hollow to provide a passageway for the cable 50therethrough. The coupling means 60 is preferably adapted to preventunnecessary contact of any external connection to the coupling means 60with the drop tube 520.

Referring now to FIGS. 1 through 3 in combination, a coupling member 70having a first side 80 and a second side 90 secures to the lower portion40 of the conduit 20. The first side 80 of the coupling member 70includes an offset portion 100. The offset portion 100 is adapted to besecured to a modified collar portion 110 at the second side 90. Thecoupling member 70 may be coupled to the conduit 20 via fasteners 115and the like, but in preferred embodiments, the coupling member 70 iswelded to the conduit 20. Regardless of the connection, the fasteners115 or welded portion is hollow to allow the cable 50 to passtherethrough. It is preferred that the composition of the couplingmember 70 is anti-corrosive, such that the rigid coupling member 70 maybe composed of stainless steel in some embodiments. It is also preferredthat the coupling member 70 be rigid or substantially rigid for fixedlysecured couplings.

Referring back to FIG. 1, a sensor assembly body 120 having an upperportion 130, a lower portion, 140, and an annular conduit 150. In thepreferred embodiment, the sensor assembly body 120 is generallycircular, but it is contemplated that the shape of the sensor assemblybody 120 may be modified. The sensor assembly body 120 preferably has acircumference having an inner diameter greater than the modified collarportion 110, such that the modified collar portion 110 may fixedlysecure the rigid coupling member 110 to the upper portion 130 of thesensor assembly body 120.

In certain preferred embodiments, the sensor assembly body 120 isconstructed of a rigid material that resists or does not deflect, anddoes not react with gasoline or other chemicals stored in the tank. Thesensor assembly body 120 is generally hollow and is open at the endadjacent the lower portion 140, such that liquid stored in the tank mayfill the sensor assembly body 120 when the tank is filled. At the lowerportion 140 of the sensor body, flow orifices 160 may be provided tofacilitate entry and removal of the level sensor mechanism 10 ingeneral, and the sensor assembly body 120 in particular from the tank.

Still referring to FIG. 1, a level sensor 170 is secured to the sensorbody 120 in the lower portion 140. At least one sensor access opening180 may be provided adjacent the position of the level sensor 170, toallow access to the level sensor 170 and any electrical connectionsextending therefrom. In a preferred embodiment, the level sensor 170 iselectrically connected to the cable 50, which extends through theannular conduit 150. The level sensor 170 may be a transducer or otherelectronic element which is adapted to measure liquid levels in thetank.

The level sensor 170 may be secured to the sensor body 120 via fastenersand the like. A body opening 185 is provided as an example of how thelevel sensor 170 could secure to the sensor body 120 via a fastener.Body opening 185 may also be used to secure the modified collar portion110 positioned on the sensor body 120. The level sensor could also besecure to the sensor body via an interference fit between the levelsensor 170 and the sensor body 120.

The cable 50 connects from the level sensor 170 and is positioned withinthe annular conduit 150. An annular conduit opening 180 is provided onthe sensor assembly 120, through which the cable may pass. From theannular conduit opening 180, the cable 50 is positioned within the lowerportion 40 of the conduit 20 and may be sealed therein via epoxy orother such sealants. It is also contemplated that the cable 50 may besealed within the annular conduit 150, although such sealing would makecable repairs and changes difficult. In a preferred embodiment, thecable 50 is preferably a jacketed coaxial cable which is impervious togasoline and other chemicals.

Referring to FIGS. 1 and 5 in combination, about the circumference ofthe sensor assembly body 120 are provided calibration points 190.Calibration points 190 are placed in predetermined positions on thesensor assembly body 120, such that the level sensor 170 may beperiodically calibrated based on the positions of the calibration points190. Also, several openings may be provided about the circumference ofthe sensor assembly body 120 to provide entry and exit points for fluidsin the tank 500.

Referring now to FIGS. 4 and 5 in combination, there is shown a sideview of the tank 500, tank fill pipe 510, drop tube 520 and level sensormechanism 10 in a partial isometric view. The level sensor mechanism 10is shown adjacent to the drop tube 520 and secured thereto by couplingmeans 60. The coupling means 60 facilitates connection between externalconnections 530 and conduit 20. The tank 500 is shown having a top 540and a bottom 550. A water level 560 and a fuel level 570 are shown inthe tank 500.

Still referring to FIG. 5, the conduit 20 is suspended between the droptube 520 and the tank fill pipe 510. The rigid coupling member 70couples the conduit 20 to the level sensor body 120. In this embodiment,the level sensor body 120 is in a parallel configuration with the droptube 520, and may rigidly depend into the tank 500, regardless of thefluid levels 560, 570. Cable 50 is shown between the level sensor body120 and the conduit 20 for providing communication between externalconnections 530 and the level sensor mechanism 170 (FIG. 1).

Referring now to FIG. 6, there is shown a partial isometric view of thetank fill pipe 510, the drop tube 520, the conduit 20, the couplingmeans 60 and the external connections 530. External connections 530 inthis embodiment comprise a threaded coupler 600 connected to a nippleportion 610, a bracket 620, and a coupling body 630. The threadedcoupler 600 is adapted to connect through the bracket 620 to a couplingbody 630. The coupling body 630 prevents the threaded coupler 600 fromcontacting the drop tube 520 and secures the threaded coupler 600 to theconduit 20. Such coupling means 60 is designed to be non-explosive, andmay include other sealing devices such as an O-ring and the like.External connections 530 may be provided and adapted to connect to thecable 50 and to the nipple portion 610.

Installation of the level sensor assembly 10 is accomplished with thetank 500 buried underground. First, the drop tube 520 is removed fromthe tank fill pipe 510. Next, a hole is provided in the side of the tankfill pipe 510. Typically, a drop tube 520 having a vertically-extending,concave indentation 580 may be utilized. The level sensor assembly 10 isrotated to an insertion position and locked in position by the couplingmeans 60. Then, the level sensor assembly 10 is lowered, sensor assemblybody 120 first, through the tank fill pipe 510 into the tank 500.

When the sensor assembly body 120 reaches the tank bottom 550, theconduit 20 may be rotated to offset the sensor assembly body 120 viacoupling member 70. Thereafter, cables 50 may be secured to externalconnections 530 and to monitoring systems, such as a personal computer,for monitoring water and gasoline levels 560, 570, respectively, or formonitoring the absence of such levels in the tank 500.

It should be understood that there are many aspects to the level sensorassembly apparatus and method, and the scope of the principles of thepresent invention should not necessarily be limited by the descriptionfound herein. It is thus believed that the operation and construction ofthe principles of the present invention will be apparent from theforegoing description of the preferred exemplary embodiments. It will beobvious to a person of ordinary skill in the art that various changesand modifications may be made herein without departing from the spiritand the scope of the invention.

The scope of the present invention is instead defined by the followingclaims.

What is claimed is:
 1. A level sensor mechanism for a storage tank,comprising: a conduit having an upper portion and a lower portion, saidconduit being adapted to receive a cable therein, said conduit beingsubstantially rigid and adapted to resist deflection; a sensor assemblybody adapted to locate a level sensor therein, said sensor assembly bodybeing located in fixed relation to said conduit, said sensor assemblybody being rigidly composed and adapted to resist deflection; a couplingmember secured to said lower portion of said conduit, said couplingmember fixedly coupling said conduit to said sensor assembly body, saidsensor assembly body being coupled on an offset portion of said couplingmember; and at least one opening located on said sensor assembly forallowing access to said sensor and said cable, and for allowing air andliquid in the storage tank to pass therethrouqh.
 2. The level sensormechanism of claim 1, further comprising: coupling means for couplingsaid conduit to a tank fill pipe, said conduit extending downward fromsaid coupling means.
 3. The level sensor mechanism of claim 1, furthercomprising: a modified collar portion secured to said sensor body andsaid coupling means, said modified collar portion having a diametersmaller than an inner diameter of said sensor assembly body and securedtherein.
 4. The level sensor mechanism of claim 1, further comprising: acable conduit positioned in said sensor assembly body, said cableconduit being adapted to receive cable from a sensor.
 5. The levelsensor mechanism of claim 1, further comprising: coupling means forconnecting said upper portion of said conduit to a tank fill pipe. 6.The level sensor mechanism of claim 5, wherein said coupling meanscomprises: a threaded coupler; a nipple portion secured to said threadedcoupler; and a coupling body engaging said threaded coupler and saidconduit.
 7. The level sensor mechanism of claim 1, wherein the levelsensor is displaced at an end of said sensor assembly body.
 8. The levelsensor mechanism of claim 1, wherein the level sensor is adapted todetect liquid levels in relation to the level sensor.
 9. The levelsensor mechanism of claim 8, wherein the level sensor communicatesdetected liquid levels to an external location via said cable.
 10. Alevel sensor mechanism, comprising: a substantially rigid conduitadapted to receive a cable therein; a substantially rigid sensorassembly body adapted to locate a level sensor therein; a couplingmember coupling said conduit to said sensor assembly body; means foroffsetting said sensor assembly body from said conduit; and couplingmeans for coupling said conduit to a tankful pipe, said conduitextending downward from said coupling means.
 11. The level sensormechanism of claim 10, wherein said level sensor is displaced at an endof said substantially rigid sensor assembly body.
 12. The level sensormechanism of claim 10, further comprising: means for connecting saidconduit to a tank fill pipe.
 13. The level sensor mechanism of claim 10,wherein said level sensor is adapted to detect liquid levels.
 14. Thelevel sensor mechanism of claim 11, wherein said level sensorcommunicates detected liquid levels to an external location via saidcable.
 15. The level sensor mechanism of claim 10, wherein the levelsensor mechanism is adapted to be placed in a storage tank havingliquids therein.
 16. The level sensor mechanism of claim 11, whereinsaid substantially rigid conduit and said substantially rigid sensorassembly body are adapted to resist deflection caused by liquids in saidstorage tank.
 17. A level sensor mechanism, comprising: means forinserting the level sensor mechanism in a storage tank; means forconnecting a sensor assembly body having a level sensor therein to asubstantially rigid conduit; means for guiding a cable through saidmeans for inserting the level sensor mechanism; means for rotating thelevel sensor mechanism about an axis while maintaining a fixedrelationship between said sensor assembly body and said substantiallyrigid conduit; means for electrically connecting the level sensor to anexternal location; means for measuring a liquid level in said storagetank and for communicating the liquid level to said external location;and means for removing the level sensor mechanism from said storagetank.
 18. A level sensor mechanism, comprising: a conduit having anupper portion and a lower portion, said conduit being adapted to receivea cable therein, said conduit being substantially rigid and adapted toresist deflection; a sensor assembly body adapted to locate a levelsensor therein, said sensor assembly body being located in fixedrelation to said conduit, said sensor assembly body being rigidlycomposed and adapted to resist deflection; a coupling member secured tosaid lower portion of said conduit, said coupling member fixedlycoupling said conduit to said sensor assembly body, said sensor assemblybody being coupled on an offset portion of said coupling member; andcoupling means for coupling said conduit to a tank fill pipe, saidconduit extending downward from said coupling means.
 19. The levelsensor mechanism of claim 18, further comprising at least one openinglocated on said sensor assembly for allowing access to the sensor andthe cable, and for allowing air and liquid to pass therethrough.
 20. Thelevel sensor mechanism of claim 18, further comprising: a cable conduitpositioned in said sensor assembly body, said cable conduit beingadapted to receive the cable from a sensor.
 21. The level sensormechanism of claim 18, further comprising: coupling means for connectingsaid upper portion of said conduit to a tank fill pipe.
 22. A levelsensor mechanism for a storage tank, comprising: a conduit having anupper portion and a lower portion, said conduit being adapted to receivea cable therein, said conduit being substantially rigid and adapted toresist deflection; a sensor assembly body adapted to locate a levelsensor therein, said sensor assembly body being located in fixedrelation to said conduit, said sensor assembly body being rigidlycomposed and adapted to resist deflection; a coupling member secured tosaid lower portion of said conduit, said coupling member fixedlycoupling said conduit to said sensor assembly body, said sensor assemblybody being coupled on an offset portion of said coupling member; and acable conduit positioned in said sensor assembly body, said cableconduit being adapted to receive cable from a sensor.
 23. The levelsensor mechanism of claim 22, further comprising: at least one openinglocated on said sensor assembly for allowing access to said sensor andsaid cable, and for allowing air and liquid in the storage tank to passtherethrough.
 24. The level sensor mechanism of claim 22, furthercomprising: coupling means for coupling said conduit to a tank fillpipe, said conduit extending downward from said coupling means.
 25. Thelevel sensor mechanism of claim 22, further comprising: coupling meansfor connecting said upper portion of said conduit to a tank fill pipe.26. A level sensor mechanism for a storage tank, comprising: a conduithaving an upper portion and a lower portion, said conduit being adaptedto receive a cable therein, said conduit being substantially rigid andadapted to resist deflection; a sensor assembly body adapted to locate alevel sensor therein, said sensor assembly body being located in fixedrelation to said conduit, said sensor assembly body being rigidlycomposed and adapted to resist deflection; a coupling member secured tosaid lower portion of said conduit, said coupling member fixedlycoupling said conduit to said sensor assembly body, said sensor assemblybody being coupled on an offset portion of said coupling member; andcoupling means for connecting said upper portion of said conduit to atank fill pipe.
 27. The level sensor mechanism of claim 26, furthercomprising: at least one opening located on said sensor assembly forallowing access to said sensor and said cable, and for allowing air andliquid in the storage tank to pass therethrough.
 28. The level sensormechanism of claim 26, further comprising: coupling means for couplingsaid conduit to a tank fill pipe, said conduit extending downward fromsaid coupling means.
 29. The level sensor mechanism of claim 26, furthercomprising: a cable conduit positioned in said sensor assembly body,said cable conduit being adapted to receive cable the cable from asensor.